1. Field of the Invention
The present invention relates to surgical instruments and, more specifically, to a surgical guide and method for properly positioning a surgical instrument with respect to an anatomical structure.
2. Description of the Related Art
The controlled positioning of surgical instruments is of significant importance in many surgical procedures and various methods and guide instruments have been developed for properly positioning a surgical instrument. Such methods include the use of surgical guides which function as mechanical guides for aligning drilling or cutting instruments. The use of such surgical guides is common in orthopedic surgical procedures and such guides may be used to properly align a drill or cutting instrument with respect to a bone when preparing the bone for receiving an implant such as an artificial joint. Computer assisted surgical procedures which involve the image guidance of a surgical instrument are also known. Image guidance techniques typically involve acquiring preoperative images of the relevant anatomical structures and generating a data base which represents a three dimensional model of the anatomical structures. The relevant surgical instruments typically have a known and fixed geometry which is also defined preoperatively. During the surgical procedure, the position of the instrument being used is registered with the anatomical coordinate system and a graphical display showing the relative positions of the tool and anatomical structure may be computed in real time and displayed for the surgeon to assist the surgeon in properly positioning and manipulating the surgical instrument with respect to the relevant anatomical structure.
In image guided procedures, a robotic arm may be used to position and control the instrument, or, the surgeon may manually position the instrument and use the display of the relative position of the instrument and anatomical structure when positioning the instrument.
Although the known methods and instrumentation which are used to properly position surgical tools provide satisfactory results, the precision obtainable with image guided surgical methods often entails the use of expensive or cumbersome equipment which may limit the use of such methods.